Pressure relief valve

ABSTRACT

A valve apparatus includes a base member having a hollow support element extending from the base member. A housing is attached to the hollow support element, and the housing includes at least one aperture. A moveable element is located within the housing and is slideably attached to the hollow support element. The hollow support element allows the moveable element to selectively travel toward and away from the base member.

FIELD OF THE INVENTION

The present invention relates generally to valves, and more particularlyto dump valves, pressure relief valves and other types of valves

BACKGROUND OF THE INVENTION

At their most basic, a valve controls the flow of a fluid or gas. Valvesare integral components in almost every gas or fluid system. A pressurerelief valve is a type of valve used to control or limit the pressure ina system. The pressure is relieved by allowing the pressurized fluid toflow through the valve and out of the system. Often, this type of valveis designed to open at a predetermined pressure to protect equipmentfrom being subjected to pressures that exceed their design limits. Whenthe set pressure is exceeded, the relief valve becomes the “path ofleast resistance” as the valve is forced open and the fluid or gas isallowed to escape. As the fluid or gas escapes, the pressure in thesystem decreases. Once it reaches the valve's reseating pressure, thevalve will close.

However, in most systems that use moving parts, there are problemsspecific to the part. Common valve problems include noise, vibration,reverse flow, sticking, leakage, component wear, or damage. In addition,valves are subject to wear—whenever one part rubs against another part,wear is a result, which leads to leakage and eventual failure of one ormore components. A component failure can result in the valve notperforming its function, which in the case of a pressure relief valve,preventing system overpressure.

Therefore, there remains a need to overcome one or more of thelimitations in the above-described, existing art. The discussion of thebackground to the invention included herein is included to explain thecontext of the invention. This is not to be taken as an admission thatany of the material referred to was published, known or part of thecommon general knowledge as at the priority date of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of a pressure reliefvalve embodying the principals of the invention, with the valve in theopen position;

FIG. 2 is an elevation view of the pressure relief valve illustrated inFIG. 1, with the valve in the open position;

FIG. 3 is a bottom perspective view of the embodiment of FIG. 1;

FIG. 4 is a sectional view taken along cutting plane A-A of FIG. 2, withthe valve in the closed position;

FIG. 5 is a sectional view taken along cutting plane A-A of FIG. 2, withthe valve in the open position; and

FIG. 6 is a close-up view taken from FIG. 5, showing the two split ringsthat are included in the embodiment of FIG. 1.

It will be recognized that some or all of the Figures are schematicrepresentations for purposes of illustration and do not necessarilydepict the actual relative sizes or locations of the elements shown. TheFigures are provided for the purpose of illustrating one or moreembodiments of the invention with the explicit understanding that theywill not be used to limit the scope or the meaning of the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the pressure relief valve apparatus and system (“PRV”)that embodies principals of the present invention. It will be apparent,however, to one skilled in the art that the pressure relief valveapparatus and system may be practiced without some of these specificdetails. Throughout this description, the embodiments and examples shownshould be considered as exemplars, rather than as limitations on thepressure relief valve apparatus and system. That is, the followingdescription provides examples, and the accompanying drawings showvarious examples for the purposes of illustration. However, theseexamples should not be construed in a limiting sense as they are merelyintended to provide examples of the pressure relief valve apparatus andsystem rather than to provide an exhaustive list of all possibleimplementations of the pressure valve apparatus and system.

Specific embodiments of the pressure valve apparatus and systeminvention will now be further described by the following, non-limitingexamples which will serve to illustrate various features. The examplesare intended merely to facilitate an understanding of ways in which theinvention may be practiced and to further enable those of skill in theart to practice the invention. Accordingly, the examples should not beconstrued as limiting the scope of the invention. In addition, referencethroughout this specification to “one embodiment” or “an embodiment”means that a particular feature, structure or characteristic describedin connection with the embodiment is included in at least one embodimentof the present invention. Thus, appearances of the phrases “in oneembodiment” or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures or characteristics maybe combined in any suitable manner in one or more embodiments.

The present invention comprises a pressure relief valve (“PRV”), and inone embodiment comprises an intake manifold vacuum-actuated valvedesigned to release pressure in the intake system of a supercharged orturbocharged engine when the throttle is lifted or closed. Generally, inan internal-combustion engine, air is compressed by a supercharger orturbocharger, (hereinafter generically referred to as “compressor”), andthen routed to an intake manifold on the engine. Between the compressorand the intake manifold is a throttle body that controls the amount ofcompressed air going from the compressor to the intake manifold. Whenthe throttle body is closed, usually by a butterfly valve, thecompressed air is trapped and a pressure wave is forced back toward thecompressor (i.e., “compressor surge”). This adds stress on the bearingsand shaft of the compressor, which can potentially break components inthe compressor.

The pressure relief valve (PRV) of the present invention is used toprevent compressor surge by providing pressure relief. The PRV islocated between the compressor and the throttle body. In one embodiment,the PRV is connected by a vacuum hose to the intake manifold. When thethrottle body is closed, the relative intake manifold pressure drops,sometimes below atmospheric pressure, and the resulting pressure drop,or vacuum, operates the PRV, which opens and allows air trapped betweenthe compressor and throttle body to escape to the atmosphere, therebypreventing compressor surge. Alternatively, the air can be recirculatedinto the engine's air intake upstream of the compressor inlet.

It will be appreciated that the PRV of the present invention may haveapplications other than internal-combustion engines. Also, as definedherein, “fluid” refers to fluid in the form of a gas, such as air fromthe atmosphere, or isolated gasses, such as hydrogen, helium, carbondioxide or other gasses. The PRV may be employed in any fluid system.

Referring now to FIGS. 1-6, a pressure relief valve apparatus (PRV) orsystem 20 is illustrated. The PRV 20 includes a base member 25 having aninlet 30 and outlets 35, which in one embodiment comprise individualapertures or vents. It will be appreciated that the number of vents oropenings 35 may vary. The inlet 30 and outlets 35 comprise a primaryfluid flow area, or opening that allows a fluid, such as air to flowthrough the base member 25 when the PRV 20 is in the open position, asshown in FIGS. 1-2 and 5.

As shown in FIGS. 4-5, a support element, or guidepost 40 extends fromthe base member 25 and includes a hollow section 45, which may betube-shaped, and that communicates with a secondary aperture, or opening50 located in a side of the base member 25. FIG. 3 shows three legs 42extending from the interior of the base member 25 to the guidepost 40.The legs 42 fix the guidepost 40 to the base member 25, and one of thelegs 42 includes the opening 50 that communicates with the hollowsection 45 of the guidepost 40, as illustrated in FIGS. 4-5. In oneembodiment, the opening 50 is sized to connect to a vacuum hose that isconnected to an intake manifold of an internal combustion engine (notshown). In other embodiments, the opening 50 can be connected to anyfluid source that can be used to open and close the PRV 20, as discussedherein.

Again referring to FIGS. 4-5, the support element or guidepost 40 alsoincludes a guidepost opening, or duct 55 located at an end of the hollowsection 45. A fluid, such as air, is able to pass from the secondaryaperture 50 in the base member 25 and continue through the hollowsection 45 and then exit the duct 55 into an interior chamber 57 of thehousing 60. The housing 60 includes the vents, or openings 35. In otherembodiments, the vents 35 may be included in the base member 25. Thatis, in the alternative embodiment, the base member 25 may be extended toinclude the vents 35, and the housing 60 would be shorter, or smaller inheight.

As shown in FIGS. 1-5, in one embodiment the housing 60 is cylindrical,but it will be appreciated that it may have other shapes. Similarly, thebase member 25 is shown as cylindrical but it will be appreciated thatan oval, elliptical or other shape may be employed. For example, thebase flange 65 may have a curved bottom to attach to a cylindrical pipe,or it may be flat, as illustrated. In one embodiment, the base flange 65is sized to enable coupling to pipes, or tubes of an internal-combustionengine.

As shown in FIGS. 4-5, located within the housing 60 is a moveableelement, or cylinder 70 that extends away from, and retracts toward thebase member 25 during operation of the PRV 20 (discussed below). Thecylinder 70 is slideably attached to the guidepost 40. As illustrated, adistal end of the guidepost 40 includes fastener threads onto which isthreaded an adjustment nut, or fastener 75. The fastener 75 is accessedby removing the housing 60 which is accomplished by unthreading housingfastener 77, and lifting the housing 60 away from the base member 25.The adjustment nut, or fastener 75 abuts a spring perch, or seat 80 thatretains a coil spring 85. As discussed in further detail below, as theadjustment fastener 75 is threaded further onto the guidepost 40, thecoil spring 85 is compressed, as the coil spring 85 is captured betweenthe spring seat 80 and the interior floor 87 of the cylinder 70. Also,the cylinder 70 includes an upper O-ring gland, or slot 90 located on aninner portion of the cylinder 70 that surrounds the guidepost 40. AnO-ring (not shown) located in the O-ring slot 90 prevents air, oranother fluid, from escaping the interior chamber 57.

A lower O-ring gland, or slot 92 is included in a base of the cylinder70 and an O-ring (not shown) located in the lower O-ring gland 92performs the function of providing a seal for the cylinder 70 when itcontacts the base member 25. This O-ring also prevents fluid fromescaping from the fluid outlet 35 when the PRV 20 is in the closedposition, as shown in FIG. 4. All of the O-rings used in the PRV 20 arethe conventional type, that is, each O-ring (not shown) located in eachgland or slot 90 and 92 comprises a gasket in the form of a ring havinga generally circular cross-section, and each is made of a pliablematerial and each is employed to provide a seal.

As shown in FIGS. 1-2 and 4-5, a distal end of the housing 60 comprisesthe fluid outlets 35, so that the distal end of the housing 60 iscomprised of legs or sections that are located between each fluid outlet35. The base member 25 includes a shoulder or lip 82 that abuts theinner portion of each housing 80 leg, thereby aligning the housing 60along an axis of the PRV 20 that extends lengthwise along a centerlineof the support element, or guidepost 40. The long axis, or centerline ofthe PRV 20 is parallel to the cut-section line A-A shown in FIG. 2.

Referring now to FIGS. 4-6, two split rings 95 are moveably located intwo ring grooves 97. FIG. 6 shows the two split rings 95 installed inthe ring grooves 97. FIGS. 4-5 show the ring grooves 97, without thesplit rings 95. The ring grooves 97 comprise a recessed area locatedaround a perimeter of the cylinder 70 and are sized to retain the splitrings 95. The ring groves 97 each include ring lands 98 that comprisetwo parallel surfaces of the ring groove 97 which function as a sealingsurface for a respective split ring 95. In one embodiment of the PRV 20,each split ring 95 comprises an expandable split ring used to provide aseal between the cylinder 70 and the moveable housing 60. The splitrings 95 are similar to conventional internal combustion piston rings inthat they comprise a circular ring that is split to facilitateinstallation.

In a preferred embodiment, each split ring 95 is made of apolytetrafluoroethylene (PTFE) material, which is a syntheticfluoropolymer of tetrafluoroethylene. The well-known brand name ofseveral PTFE-based formulas is TEFLON (TEFLON is a registered trademarkof E.I. du Pont de Nemours and Company of Wilmington, Del.). It will beappreciated that the split rings 95 used in the PRV 20 may bemanufactured from other materials. One type of split ring 95 that may beemployed by the PRV 20 includes a split ring manufactured by HerculesSealings Products of Canada (part 575-224ST PTFE back-up ring). It willbe appreciated that the PRV 20 may employ only one split ring 95 or thePRV 20 may use three split rings 95.

As employed in the PRV 20, the split rings 95 seal the interior chamber57, preventing any fluid leakage during operation of the PRV 20. Asmentioned above, the PRV 20 is a pressure relief, or dump valve.Generally, a conventional dump valve employs a poppet valve having aspring to keep it closed and a diaphragm actuator to open the valveduring engine decelerations when the engine's intake manifold provides avacuum. However, air is trapped between the lower side of the diaphragmand the housing with the valve guide. That pressure must be vented,usually through restrictive ports, to allow movement of the diaphragm.This venting process slows the valve action. One feature of the PRV 20is the latent pressure that slows the operation of conventional dumpvalves is non-existent.

As installed on an internal combustion engine having supplementalatmospheric boost pressure provided by a supercharger or turbocharger(hereinafter generically referred to as a “compressor”), the PRV 20 baseflange 65 is attached to a duct to be vented. The attachment can be byvarious means, including a v-band, or other means. A portion of thefluid, such as air passing through the duct moves into the fluid inlet30, where it may be vented through the fluid outlet 35 or sealed,depending on the operational mode of the PRV 20. Unlike the conventionalvalves, the control pressure inlet, in the form of the secondaryaperture 50, is on the side of the base member 25, just above the baseflange 65.

During idle of an internal combustion engine having a compressor, fluidpressure at the secondary aperture 50 is at a moderate vacuum, and fluidpressure at the fluid inlet 30 is at a moderately higher pressure thanambient. In this condition, the PRV 20 may be partially open, dependingon the spring 85 adjustment. That is, the cylinder 70 may be positionedaway from the base 25, so that fluid can pass through the fluid inlet 30and escape out through the fluid outlets 35. The amount of opening ofthe PRV 20 is mainly controlled by the spring 85. As mentioned above,the adjustment fastener 75 can be rotated to adjust a pre-load on thespring 85. Changing the spring 85 pre-load will change when the PRV 20is actuated, or opened. The condition where the PRV 20 may be partiallyopen is also possible when the engine is operating at cruise, or in apartial-throttle setting. Again, this is variable, depending on thepre-load on the spring 85.

In the case when the compressor is operating, and is providing boosted,or higher-than atmospheric pressure air to the internal combustionengine, the fluid pressure at the secondary aperture 50 and at the fluidinlet 30 are approximately equal, so the PRV 20 is closed, as shown inFIG. 4.

When the engine's throttle is lifted or closed, a difference in pressurebetween the air in the interior chamber 57 and the air at the fluidinlet will cause the cylinder 70 to move away from the base member 25,allowing air to pass through the fluid inlet 30 and out the fluidoutlets 35. For example, as discussed above, between the compressor andthe intake manifold is a throttle body that usually comprises abutterfly valve. When the throttle is “closed” the butterfly valveblocks air from flowing to the engine's intake manifold, and thecompressed air is trapped and a pressure wave is forced back toward thecompressor (i.e., “compressor surge”). This adds stress on the bearingsand shaft of the compressor, which can potentially break components inthe compressor. In this situation, with the PRV 20 located between thethrottle body and the compressor, the fluid pressure at the secondaryaperture 50 is a vacuum, as it is connected to the engine's intakemanifold, which is no longer receiving air from the compressor. However,the fluid pressure at the fluid inlet 30 of the PRV 20 will berelatively high, as it is receiving air that is trapped between thethrottle body and compressor.

As shown in FIG. 5, in the situation described immediately above, thefluid pressure inside the interior chamber 57 will be a vacuum, oralmost a vacuum, as fluid may be removed from the interior chamber 57through guidepost duct 55, down the hollow tube 45 and out the secondaryaperture 50 to the intake manifold. The high fluid pressure located atthe fluid inlet 30 now pushes against the cylinder 70 base, resulting ina high fluid pressure differential between the interior chamber 57 andthe fluid inlet 30. The pressure differential pulls and pushes thecylinder 70 away from the base member 25, thereby compressing the spring85, and allowing the fluid to escape through the fluid outlets 35.

When the pre-load on the spring 85 is able to exceed the force the fluidpressure exerts against the cylinder 70, the spring 85 pushes thecylinder 70 toward the base member 25, so that the O-ring located in thebase of the cylinder 70 contacts the base member 25 and stops fluid flowthrough the fluid outlets 35.

One feature of the PRV 20 is that it provides a relatively large areafor fluid to escape. That is, when compared to similar sizedconventional type valves, the total area (through fluid outlets 35)available for fluid escape is much greater than the area available whena poppet-type valve opens.

Another feature of the PRV 20 is that the split rings 95 generate verylittle friction resistance. That is, the cylinder 70 can move away from,and toward the base member 25 very quickly and easily so that the PRV 20can quickly operate to prevent fluid pressure from damaging thecompressor.

In contrast to a piston ring in an internal combustion engine, wherehigh pressure from combustion forces the piston to move, the cylinder 70in the PRV 20 moves as a result of a pressure differential. As thecylinder 70 extends away from the base member 25, the split rings 95mounted in the cylinder 70 move a small amount to lodge against thelower land 98. Then, as the fluid escapes through the fluid outlets 35,and the fluid pressure differential drops, the cylinder 70 retractstoward the base member 25, and the split rings 95 move a small amount tolodge against the opposite land 98. Put differently, the action of thesplit rings 97 and cylinder 70 is opposite to that of the movement of apiston within a cylinder of an internal combustion engine. The splitrings 95 may have a minimal amount of air flow through the gap, or splitin each split ring 95 (the gap, or split in each split ring 95 isrequired to allow each split ring 95 to be expanded so that it can beinstalled in its respective ring groove 97).

It will be appreciated that the PRV 20 may be manufactured in manydifferent sizes, to suit any application. For example, for smallerengines, a diameter of the fluid inlet 30 may be 50 millimeters, but forlarger engines the diameter of the fluid inlet 30 may be 63 millimeters,or 76 millimeters or larger. In an application where the diameter wherethe fluid inlet 30 is 63 millimeters, the outer diameter of the cylinder70 may be two and one-half inches (2.5″). NOTE: these valves, Onefeature of the PRV 20 is the location of the secondary aperture 50,which in a preferred embodiment, a vacuum tube may be coupled to thesecondary aperture 50, and the vacuum tube can now be routed adjacent tothe duct that the PRV 20 is coupled to. This is in contrast toconventional poppet-style valves that have a vacuum tube connected attheir distal end, which positions the vacuum tube perpendicular to theduct.

Thus, it is seen that a pressure relief valve apparatus, system andmethod is provided. One skilled in the art will appreciate that thepresent invention can be practiced by other than the above-describedembodiments, which are presented in this description for purposes ofillustration and not of limitation. The specification and drawings arenot intended to limit the exclusionary scope of this patent document. Itis noted that various equivalents for the particular embodimentsdiscussed in this description may practice the invention as well. Thatis, while the present invention has been described in conjunction withspecific embodiments, it is evident that many alternatives,modifications, permutations and variations will become apparent to thoseof ordinary skill in the art in light of the foregoing description.Accordingly, it is intended that the present invention embrace all suchalternatives, modifications and variations as fall within the scope ofthe appended claims. The fact that a product, process or method exhibitsdifferences from one or more of the above-described exemplaryembodiments does not mean that the product or process is outside thescope (literal scope and/or other legally-recognized scope) of thefollowing claims.

It is to be noticed that the term “comprising”, used in the claims,should not be interpreted as being limitative to the means listedthereafter. Thus, the scope of the expression “a device comprising meansA and B” should not be limited to devices consisting only of componentsA and B. It means that with respect to the present invention, the onlyrelevant components of the device are A and B. Similarly, it is to benoticed that the term “coupled”, also used in the claims, should not beinterpreted as being limitative to direct connections only. Thus, thescope of the expression “a device A coupled to a device B” should not belimited to devices or systems wherein an output of device A is directlyconnected to an input of device B. It means that there exists a pathbetween an output of A and an input of B which may be a path includingother devices or means. Also, “coupled” may mean attached in a fixedmanner, or attached so that relative movement between one or elements ispossible. Finally, the terms “a”, “an” and “the” mean “one or more”,unless expressly specified otherwise.

What is claimed is:
 1. A valve apparatus, comprising: a base memberhaving a hollow support element extending therefrom; a housing coupledto the hollow support element, the housing including at least oneaperture; and a moveable element located within the housing andslideably coupled to the hollow support element, the hollow supportelement allowing the moveable element to selectively travel toward andaway from the base member; further comprising a split ring moveablycoupled to the moveable element, with a portion of the split ringabutting the housing.
 2. The valve apparatus of claim 1, furthercomprising: a spring seat adjustably coupled to the hollow supportmember; and a spring located between the spring seat and the moveableelement.
 3. The valve apparatus of claim 1, where the hollow supportelement comprises: a first end having an opening in fluid communicationwith an aperture located in the base member; a second end coupled to thehousing; and an aperture located adjacent to the second end, theaperture in fluid communication with an interior of the housing and anupper surface of the moveable element.
 4. The valve apparatus of claim1, where the base member includes a flange structured to removablycouple to a fluid source.
 5. The valve apparatus of claim 1, where thebase member includes an aperture communicating with an air source thatis selectively less than, or greater than, an ambient air pressure. 6.The valve apparatus of claim 1, where the housing is removeable so thata spring preload fastener can be accessed to adjust a preload of aspring located between a spring seat adjustably coupled to the hollowsupport element and the moveable element.
 7. A valve apparatus,comprising: a base member having a hollow support element extendingtherefrom, the base member including a first and a second aperture, withthe first aperture in fluid communication with the hollow supportelement; a housing coupled to the support element, the housing includingat least one aperture; and a moveable element located within the housingand slideably coupled to the hollow support element, the moveableelement sized to cover the at least one aperture on the housing; wherethe hollow support element allows the moveable element to selectivelytravel toward and away from the base member, so that when the moveableelement is positioned away from the base member the at least oneaperture on the housing is in fluid communication with the secondaperture in the base member; further comprising at least one split ringmoveably coupled to the moveable element, with a portion of the splitring abutting the housing.
 8. The valve apparatus of claim 7, furthercomprising: a spring seat adjustably coupled to the hollow supportelement; and a spring located between the spring seat and the moveableelement.
 9. The valve apparatus of claim 7, where the hollow supportelement comprises: a first end having an opening in fluid communicationwith the first aperture located in the base member; a second end coupledto the housing; and an aperture located adjacent to the second end, theaperture in fluid communication with an interior of the housing and anupper surface of the moveable element.
 10. The valve apparatus of claim7, where the second aperture in the base member communicates with an airsource that is less than an ambient air pressure.
 11. The valveapparatus of claim 7, where the housing is removeable so that a springpreload fastener can be accessed to adjust a preload of a spring locatedbetween a spring seat adjustably coupled to the hollow support elementand the moveable element.
 12. A method of changing a fluid pressure in apressurized system, the method comprising the steps of: providing ahollow housing having an inlet and an outlet, and an aperture extendingthrough the hollow body; providing a hollow support element coupled tothe hollow housing, the hollow support element in fluid communicationwith the aperture in the hollow housing; and providing a moveableelement slideably coupled to the hollow support element, the moveableelement located within the hollow housing and sized to cover the outletin the hollow housing; where the fluid pressure in the pressurizedsystem enters the inlet in the hollow housing and moves the moveableelement so that the fluid pressure flows through the outlet in thehollow housing; further comprising the step of: selectively providingeither a lower than ambient air pressure, or a greater than ambient airpressure to the interior of the hollow housing through the aperture andthrough the hollow support element, which causes the moveable element torespectively cover the outlet in the hollow housing or un-cover theoutlet in the hollow housing, thereby changing a fluid pressure in thepressurized system.
 13. The method of claim 12, where the hollow supportelement comprises: a hollow tube having an opening in fluidcommunication with the aperture located in the hollow housing; anaperture located at a distal end of the hollow tube, the aperture influid communication with an interior of the hollow housing and a uppersurface of the moveable element.